| 摘要 |
A toggle linkage over-center mechanism employs first and second solid, metal links having facing axial ends pivoted to each other for pivoting about a first axis, the first link is pivotably coupled at one end to the fixed support for pivoting about a second pivot axis. The second link has an opposite axial end pivotably coupled about a third axis to an element for causing over-center movement of the pivotably coupled first and second links through a center line defined by the first and third pivot axes. Tension coil springs having opposite ends are pivotably coupled to respective outboard ends of the pivotably coupled first and second links. One of the rigid metal links is adjustable over its length to preload the tension coil springs to a sufficient magnitude to maintain preload tension within the over-center toggle linkage mechanism over the full range of movement of the toggle links between oppositely oblique over-center positions. The pivot axis between the end of the second link remote from the pivot connection between the first and second links defines a free pivot axis which moves relative to the fixed support. An actuator stem is pivotably mounted to the first link for pivoting about an axis parallel to the first, second and third pivot axes. The second link may be of dumbbell configuration and consist of two axial sections each having a cylindrical head, with one head having a tapped bore receiving a fine thread cylindrical shank sized and threaded to the tapped bore. Relative rotation between the two sections of the second link effect axial length adjustment of that link.
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